Vascular permeability is tightly regulated during blood vessel development and it is indispensable for normal organ function throughout adult life. Many life-threatening pathological conditions, including acute respiratory distress syndrome (ARDS), atherosclerosis, cancer, and organ failure are caused or complicated by compromised vascular barrier function. In ARDS—a devastating pulmonary complication that often occurs with sepsis caused by systemic infection—excess fluid leaks out of the lung capillaries and fills the adjacent alveolar air spaces causing pulmonary edema; this fluid impairs gas exchange across the alveolar membrane, decreases lung compliance and severely compromises respiratory function. ARDS occurs in almost half of severe sepsis cases in human patients and combination of sepsis and ARDS is associated with a mortality of 60%. Despite a great amount of effort in this area, currently there is no specific clinical therapy for ARDS or any other condition caused by abnormal vascular permeability. Accordingly, there is a need in the art for modulating vascular permeability and treatments for conditions wherein vascular permeability plays a part.